Background: To identify factors that may have augmented local risks for variant Creutzfeldt-Jakob disease (vCJD).
Methods: Descriptive study of local investigations of UK vCJD cases, who had lived close together at some point since 1980.Main outcome measures: domestic, educational, occupational, health care associated, social and recreational links between cases; common dietary, iatrogenic and other possible routes of exposure to vCJD infection; locally elevated vCJD risk.
Results: A cluster of five cases of vCJD in a rural area in North Leicestershire was investigated in 2000, (P=0.004). A further 12 investigations of geographically associated cases of vCJD have been undertaken in the UK. In nine of the 12 locations, some or all of the local cases had consumed beef purchased from the same local retail outlets or provided by a common supplier of school meals, or had some aspect of their medical-dental care in common. In only three of these locations were circumstances identified where the local risk of transmission might have been elevated. In none of the locations was there strong evidence to exclude chance as a likely explanation for the local occurrence of these vCJD cases (P≥0.7 for all locations, except Northern Ireland where analysis not performed).
Conclusion: Although it is possible that in some parts of the UK local factors may have increased the risk of acquiring vCJD, most cases that were geographically close to each other are likely due to the same factors that gave rise to the large majority of other vCJD cases in the UK.